Supported file formats:
.mp3, .m4a, mp4, .m4v, .mpg, pdf, .zip.
Supported images formats:
.jpg, .gif, and .png.
The recommended stereo bit rate and sample rate for audio files:
Stereo Bit Rate: 128 kbps
Sample Rate: 44.1 kHz
The maximum allowed single file size: 3GB.
The maximum allowed single image file size: 1 MB.
In order to be better compatible with iTunes, iPad/tablets, and mobile, we highly recommend you use Mp3 or H.264 based mp4 and m4v.